One known type of vehicle, such as e.g., a hybrid car has both an engine and a dynamotor disposed therein as a power source. The hybrid car further has the dynamotor positioned between the engine and a transmission, thereby forming a composite power unit.
Such a composite power unit is disclosed in published Japanese Patent Application Examined No. 62-29979, granted Patent No. 2708469, and Japanese Patent Applications Laid-Open No. 9-215270, No. 10-80098, and No. 11-78555.
The above Application Nos. 10-80098 and 11-78555 disclose examples of conventional composite power units. In such examples, the dynamotor is disposed between an internal combustion engine and a flywheel.
However, as disclosed in the above publication, the flywheel is spaced apart from the crankshaft. Such positioning brings about an inconvenience in that vibrations cause the crankshaft to undergo an increased level of bending stress and torsional vibration, which is thus disadvantageous in view of practical use.
In addition, the dynamotor is in the way when a starter motor is disposed toward the engine. Consequently, the starter motor cannot be placed there.
In a front wheel-driven vehicle having the engine disposed therein in a transverse direction of the vehicle, a drive shaft is disposed so as to be close to both a transmission case of the transmission and the engine.
The flywheel has the greatest diameter in the transmission case in order to insure a large moment of inertia.
According to the above Application Nos. 10-80098 and 11-78555, a stator of the dynamotor has an outer diameter greater than that of the flywheel. This causes another inconvenience in that layout of components including the transmission must be changed in order to prevent interference with the drive shaft, which is then disadvantageous in view of practical use.
In order to obviate or at least minimize the above inconveniences, the present invention provides a composite power unit having an engine and a dynamotor both provided therein as a source of drive for a vehicle and further having the dynamotor disposed between the engine and a transmission. The composite power unit includes a crankshaft supported on a cylinder block of the engine; a flywheel arrangement mounted on the crankshaft at one end thereof, the flywheel arrangement being formed by a disk-like first flywheel and a second flywheel in which the first flywheel is positioned toward the engine, while the second flywheel is disposed toward the transmission; a rotational sensor and the dynamotor both disposed between the first and second flywheels, the sensor and the dynamotor being arranged in sequence from the side of the engine; a flange-like clutch-receiving surface disposed on the second flywheel at an end thereof toward the transmission; and a clutch attached to the clutch-receiving surface, the clutch being covered by a transmission case of the transmission.
According to the present invention, the first flywheel, the rotational sensor, the dynamotor, the clutch-receiving surface of the second flywheel, and the clutch are disposed in this order from the engine side toward the transmission. As a result, the inertial moment of the flywheel arrangement is positioned close to one end of the crankshaft, thereby reducing both bending stress and torsional vibration to be exerted on the crankshaft.